Valkanis, a foundation player with the club, was shocked by a turn of events, which has thrust him into the top job and strongly refuted suggestions he undermined Kosmina or had aspirations to take his job.

But he has vowed to give his all in helping the Reds mount a challenge for the title and urged his players to make the most of their standing in the top four, six points behind leaders Central Coast Mariners.

"Basically [I told them] that the club is bigger than anyone and we've got a big job at hand and a great opportunity for all of us to achieve something big," Valkanis said .

"We need to focus on winning games and improving day in, day out on the park."

Kosmina cited a lack of trust in his working environment for his resignation, with speculation he accused Valkanis of being after the top job.

Valkanis, who played under Kosmina in the club's early years, acknowledges the pair had a "discussion" after last week's 3-1 loss to the Mariners but insists there is no truth to the rumours.

"I have great respect for Kossie and played under him and played good football under him and worked very hard," Valkanis said.

"As assistant coach I did everything that he asked me to do and even more sometimes. I worked very hard at it.

"... I've never spoken to the club about the head coach's role and the club never spoke to me.

"For me, I was always the assistant and the youth team coach and I really enjoyed that role.

"Obviously now the circumstances have chosen that I've got to fulfil this role for the rest of the season and I'll do that at the best of my ability, like I've always done.

"I'll expect all the boys to follow suit."

Valkanis admits the dramatic events have not been a good look for the club but says the best way to win supporters back is by impressing on the park.

"You'd like to have stability at a club but I think the only way to fix the branding is to play good football and to win games," he said.

"From day one this club has had great support.

"Along the way it's sort of fallen off for whatever reason but everyone's got to jump back on board because we've got a really good team that is right up there."

The Reds can ill afford to let results slip any further after two successive losses.

They face fellow top-four sides Western Sydney Wanderers and Melbourne Victory in their next two matches.